TY  - JOUR
A1  - Debsharma, Tapas
A1  - Schmidt, Bernd
A1  - Laschewsky, Andre
A1  - Schlaad, Helmut
T1  - Ring-opening metathesis polymerization of unsaturated carbohydrate derivatives
T2  - Macromolecules : a publication of the American Chemical Society
N2  - A series of biomass-derived levoglucosenyl alkyl ethers (alkyl = methyl, ethyl, n-propyl, isopropyl, and n-butyl) were synthesized and polymerized by ring-opening olefin metathesis polymerization using the Grubbs catalyst C793 at room temperature. Polymerizations were successfully performed in conventional solvents such as 1,4-dioxane and dichloromethane as well as in polar aprotic "green" solvents such as 2-methyltetrahydrofuran, dihydrolevoglucosenone (Cyrene), and ethyl acetate. The prepared polyacetals with degrees of polymerization of similar to 100 exhibit Schulz-Flory-type molar mass distributions and are thermoplastic materials with rather low glass transition temperatures in the range of 43-0 degrees C depending on the length of the alkyl substituent. Kinetic studies revealed that the polymerization proceeded rapidly to a steady state with a certain minimum monomer concentration threshold. When the steady state was reached, just about half of the [Ru] catalyst had been effective to initiate the polymerization, indicating that the initiation step was a slow process. The remaining catalyst was still active and did no longer react with monomers but with in-chain double bonds, cutting the formed polymer chains into shorter fragments. In the long term, all catalyst was consumed and propagating [Ru] chain ends were deactivated by the elimination of [Ru] from the chain ends to form inactive chains with terminal aldehyde groups.
Y1  - 2021
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/60056
SN  - 0024-9297
SN  - 1520-5835
VL  - 54
IS  - 6
SP  - 2720
EP  - 2728
PB  - American Chemical Society
CY  - Washington
ER  -